Hyperkeratosis
| Classification according to ICD-10 | |
|---|---|
| L85.9 | Epidermal thickening, unspecified |
| ICD-10 online (WHO version 2019) | |
As hyperkeratosis (from Greek hyper , over '; keratos , horn') is defined as the excessive keratinization of the skin . The outermost layer of the epidermis, the stratum corneum , becomes thicker over a large area or only selectively thicker.
Subtypes
A distinction is made between subtypes according to the underlying mechanism.
Proliferation hyperkeratosis
In proliferation hyperkeratosis , the stratum corneum is thickened because the cell division in the stratum basale is accelerated. In the same period of time, more keratinocytes are formed, resulting in more corneocytes .
Retention hyperkeratosis
In the retention hyperkeratosis (from latin retentio , retention ') leads to thickening of the stratum corneum , since the exfoliation of the corneocytes from the disjunctum stratum is hindered.
causes
Hyperkeratoses can have exogenous and endogenous causes.
Mechanical stimuli
With mechanical stress (especially through pressure) the skin is stimulated to the increased formation of keratinocytes or corneocytes , as a result the stratum corneum - limited to the stressed region - becomes thicker (proliferation hyperkeratosis).
In humans , the stratum corneum thickens, especially on the soles of the feet, as a result of the particular stress caused by pressure (body weight) and friction. It formed calluses . Such changes are also possible in other parts of the body with appropriate stress.
Arsenic as an environmental toxin
Hyperkeratosis can also indicate chronic arsenic poisoning .
UV radiation
Ultraviolet radiation can lead to hyperkeratosis and even the formation of light calluses.
When UV radiation hits the skin, cell division in the stratum basale is accelerated. More keratinocytes migrate to the surface of the skin, the stratum corneum becomes thicker (proliferation hyperkeratosis).
The therapeutic effect of UV and sunlight on acne is therefore ambivalent: on the one hand, UV radiation has an antibacterial effect, on the other hand it promotes proliferation hyperkeratosis - also in the sebum follicle . This can lead to the formation of new comedones .
Comedogenic substances
Comedogenic substances promote the formation of comedones . This corresponds to hyperkeratosis confined to the sebum follicle . As a rule, due to their material properties, comedogenic substances prevent the exfoliation of the corneocytes (horn cells) from the stratum disjunctum , so that retention hyperkeratosis occurs.
Genetic predisposition and metabolic changes
Hyperkeratoses can be genetically predisposed or caused by changes in the metabolism. Examples of this are keratosis pilaris and hyperkeratoses in endogenous acne , chronic eczema and psoriasis .
Hereditary pad hyperkeratosis occasionally occurs in dogs .
treatment
Several keratolytic agents are available for the cosmetic and medical treatment of hyperkeratosis ( keratolysis ) . Androgen- dependent hyperkeratoses in female patients can u. U. hormonally be treated. Pumice , Hornhautraspeln, Callus and mechanical exfoliants are used to abrasive treatment of hyperkeratotic lesions.
See also
Individual evidence
- ↑ Alphabetical directory for the ICD-10-WHO version 2019, volume 3. German Institute for Medical Documentation and Information (DIMDI), Cologne, 2019, p. 386
- ↑ a b Hyperkeratose In: Roche Lexikon Medizin , 4th edition; Urban & Fischer 1999. Online ( Memento from September 11, 2007 in the Internet Archive )
